EP276 - De Novo Colonic Adenocarcinoma in the Pediatric Population

Purpose/Background: De novo colon and rectal adenocarcinoma is a growing public health crisis in the young adult population. However, this disease remains exceedingly rare in the pediatric and juvenile populations, especially in the absence of genetic mutations or significant family history such as familial adenomatous polyposis. It is estimated that approximately one in 10 million children under the age of 20 years are affected, with a peak at around 15 years old. The literature on this topic remains sparse.

Methods/Interventions: We present the case of a 16-year-old female patient with no significant past medical, surgical, or family history who presented with 6 months of progressive abdominal pain in the left lower quadrant, intermittent diarrhea, and emesis. Initial imaging was concerning for a colo-colonic fistula between sigmoid and transverse colon, suggestive of inflammatory bowel disease. Additionally, there was a focal mass-like appearance along the mesentery with extensive inflammatory changes in the lower abdominopelvic peritoneal cavity (Figure 1). Additional CT chest ruled out any distant metastatic disease. Colonoscopy revealed localized moderate inflammation characterized by edema and pseudo polyps in the descending colon that were unable to be traversed further proximally. Biopsy and hot snare excision of the polyps were examined and found to be a well differentiated invasive adenocarcinoma with preserved mismatch repair protein status (MLH-1, MSH-2, MSH-6, PMS-2 intact). The patient ultimately underwent an extended left hemicolectomy and stapled side-by-side colonic anastomosis. Intra-operatively, the mass involved both the sigmoid and transverse colon and was found to be densely adherent to the anterior abdominal wall and superior dome of the bladder (Figure 2).

Results/Outcomes: Final surgical pathology confirmed 33/33 negative regional lymph nodes, negative margins, and an ultimate diagnosis of pT4bN0 (Stage IIc) invasive adenocarcinoma with both perineural and lymphovascular invasion. She tolerated the procedure well and will begin adjuvant chemotherapy with FOLFOXIRI soon.

Conclusion/Discussion: Although rare, pediatric colorectal adenocarcinoma should be considered in children presenting with vague abdominal symptoms often attributed to more common pathologies such as inflammatory bowel disease. This case underscores the importance of early recognition and highlights the value of a multi-disciplinary approach between adult colorectal and pediatric surgery teams to optimize care for these patients.

Initial CT imaging
Fistulizing colonic mass